The present invention relates to the display of images on a display device and, in particular, to a fast process for zooming-in and out of images, to the layout and associated zooming of image thumbnails for image browsing, and to the encoding and scaling of image thumbnails for fast display of multiple images at varying resolutions in applications such as image browsing.
As the price of digital cameras continues to fall, and as personal computers become increasingly more powerful, the number of digital images managed by home and small business computer users is set to increase dramatically in the very near future. Despite this, the need for software image browsers to move beyond the limitations of the current design conventions to support effective browsing of many thousands of images has received relatively little attention. Further, despite the large number of digital images commonly encountered by users, fixed size image thumbnails or image icons continue to be used as the basis for designing conventional image browsing applications.
Existing image browsers are based on the concept of displaying fixed size image thumbnails to users. Image thumbnails are small copies of actual image files that the thumbnails represent. Typically, thumbnails are displayed at between 80xc3x9780 pixels and 120xc3x97120 pixels. This allows visual display screens to display between 9 and 25 thumbnails at any one time depending on the screen and thumbnail resolutions, and the interface design. Consequently, when browsing large numbers of image thumbnails, users are unable to see more than a small proportion of the images of interest and are typically forced to scroll through vast arrays of thumbnails. This results in significant browsing and orientation problems.
The fixed resolution at which designers of existing image browsers choose to display thumbnails represents a trade off between the two primary uses of thumbnails in image browsers, those being browsing image content and assessing image content. Browsing image content is defined here as briefly scanning or glancing at image thumbnails to gain an overview of the images available. Browsing content is limited by the number of thumbnails that can be displayed at once. Assessing image content is a closer examination of image thumbnails and the assessment of detail, and is limited by the resolution of thumbnails that can be displayed.
Conventional approaches to the use of thumbnails have a number of disadvantages including the display of only a portion of fixed size thumbnails in a display area not large enough to display all the thumbnails and the use of scroll bars. Both of these contribute to user disorientation, general difficulty of navigating an image space, and an inconsistent spatial representation of the image space, amongst other things.
Besides the disadvantages of only displaying only a portion of fixed size thumbnails, using scroll bars making navigation of an image space difficult, and providing an inconsistent spatial representation of the image space, such fixed size thumbnails themselves can use large amounts of memory or alternatively take relatively long period to decompress from compressed image storage. For example, a conventional method of thumbnail zooming-involves performing progressive decompressions of the thumbnail image until the desired image is obtained. This provides for a representative depiction of the zoom as seen by the user but involves performing a number of complex decompressions in succession. This has been found to consume valuable processor and operator time which is undesirable.
Thus, a need clearly exists for a method of providing thumbnails that are not fixed in size, have reduced memory requirements, are capable of rapid scaling, and provide for improved browsing applications.
It is an object of the present invention to substantially overcome, or at least ameliorate, one or more problems associated with prior arrangements.
In accordance with a first aspect of the present invention there is provided a method of zooming an image on a display device, said method comprising the steps of:
displaying a first representation of said image at a first predetermined size, said first representation having a first predetermined resolution;
stretching or shrinking the first representation to provide one or more modified representations;
successively displaying said one or more modified representations; and
thereafter displaying a further representation of said image at a second predetermined size, said further representation having a further predetermined resolution;
wherein said further predetermined size and resolution are different to said first predetermined size and resolution.
Preferably, the one or more other predetermined sizes are intermediate a first and second predetermined size. In the event where the first image is being stretched, the second image is preferably a greater resolution version of the first image and where the first image is being shrunk the second image is preferably a lower resolution version of the first image. Typically, the first and second image are stored in a memory storage device (eg.: CD-ROM hard drive, floppy drive, RAM, ROM card) in a compressed representation, and preferably are a first and second resolution of the same image respectively.
In accordance with a second aspect of the invention, there is provided a method of zooming thumbnails of digital images for use in image browsing, the method comprising the steps of:
laying out the thumbnails in at least one containment area having the same aspect ratio as an available display area of a display device; and
scaling the thumbnails contained in the at least one containment area to fit within the available area of the containment area.
Preferably, the method further comprises the step of increasing the scale of the thumbnails if increased detail of the thumbnails is required for assessment. More preferably, the thumbnails are scaled to be as large as possible and fit within the available display area.
The method may further comprise the step of organising the thumbnails into two or more groups in respective containment areas, and the groups may have a hierarchical structure. Still further, one or more groups laid out in respective containment areas may comprise two or more (sub)groups of thumbnails laid out in respective (sub)containment areas, each (sub)containment area having the same aspect ratio as the parent containment area and the displayable area.
In accordance with a third aspect of the invention, there is provided an apparatus for zooming digital images for use in image browsing, said thumbnails being displayable on a display module, the apparatus comprising:
a device for laying out the thumbnails in at least one containment area having the same aspect ratio as an available display area of a display module; and
a device for scaling the thumbnails contained in the at least one containment area to fit within the available area of the containment area.
Preferably, the apparatus comprises a computer and a computer readable medium having recorded thereon a computer program for zooming the digital images, the computer program carrying out the method described above, wherein the computer program can be loaded into and run by the computer to implement the apparatus.
In accordance with a fourth aspect of the invention, there is provided a computer program product having a computer readable medium having a computer program recorded thereon for zooming digital images for use in image browsing, the digital images each having a corresponding thumbnail, the computer program product comprising:
a module for laying out the thumbnails in at least one containment area having the same aspect ratio as an available display area of a display module; and
a module for scaling the thumbnails contained in the at least one containment area to fit within the available area of the containment area.
In accordance with a fifth aspect of the invention, there is provided a method of scaling thumbnails representing digital images, the method comprising the step of encoding a digital image using a hierarchical representation to provide a thumbnail. Further, the method includes the step of decoding the hierarchical representation of the digital image at a predetermined one of a plurality of scales to provide the thumbnail having a desired size. The scale of the decoded hierarchical representation may be equal to or greater than the desired size of the thumbnail.
Still further, the method may include the step of downsampling the decoded hierarchical representation to provide the desired size thumbnail if the scale of the decoded hierarchical representation is greater than the desired size of the thumbnail. Alternatively, it may include the step of upsampling the decoded hierarchical representation to provide the desired-size thumbnail if the scale of the decoded hierarchical representation is less than the desired size of the thumbnail. The method may also include the step of decoding the hierarchical representation of the digital image at two different adjacent scales of a plurality of scales to provide the thumbnail having a desired size. The two decoded hierarchical representations having different adjacent scales can be interpolated to provide the desired-size thumbnail if the scale of one of the two decoded hierarchical representations is greater than the desired thumbnail size and the other of the two decoded hierarchical representations is less than the desired thumbnail size. The method may further comprise the step of displaying the thumbnail.
Preferably, the encoding step includes the step of applying a hierarchical discrete wavelet transform to the image. Advantageously the encoding comprises SWEET encoding. Compressed thumbnails and decompressed versions of thumbnails at particular sizes may be cached. Optionally, intermediate scales of decompressed thumbnails may also be cached.
In accordance with a sixth aspect of the invention, there is provided an apparatus for scaling thumbnails representing digital images, the apparatus comprising:
means for storing a thumbnail, the thumbnail comprising a hierarchically encoded representation of a digital image; and
means for decoding the hierarchical representation of the digital image at at least a predetermined one of a plurality of scales to provide the thumbnail having a desired size.
In accordance with a seventh aspect of the invention, there is provided a computer program product comprising a computer readable medium having a computer program recorded thereon for scaling thumbnails representing digital images, the computer program product comprising:
means for storing a thumbnail, the thumbnail comprising a hierarchically encoded representation of a digital image; and
means for decoding the hierarchical representation of the digital image at at least a predetermined one of a plurality of scales to provide the thumbnail having a desired size.
Many other aspects of the invention and present disclosure will become apparent on review and understanding the following descriptions and claims.